Squamous Cell Carcinoma, Esophagus, Rat

Abstract

According to their pattern of growth, squamous cell carcinomas of the esophagus are classified as exophytic and endophytic varieties (Cardesa et al. 1982). Exophytically growing carcinomas have a cauliflower-like shape, with markedly irregular contours, friable consistency, and whitish color. Occasionally, foci of hemorrhage and necrosis are seen on the surface. They give rise to protruding, broad-based, confluent, nodular formations measuring an average of 1cm in diameter (Fig. 277). Due to their large size, they usually cause obstruction of the esophagus with dilatation of its proximal part. In endophytic carcinomas, there is a limited intraluminal growth. The tumor surface is irregular, necrotic, and hemorrhagic, showing erosions and defects that, in advanced carcinomas, give rise to wide annular ulcerations, reaching up to 1.5 cm in length (Fig. 278). The cut surface is whitish to whitish-red, showing conspicuous thickening of the esophageal wall due to the inward growing of the tumor. In some advanced carcinomas, however, a mixed pattern of exophytic and endophytic growth is observed. Both of the patterns may be so intermingled that an objective distinction of the type of growth is no longer possible.